Arianna Huffington’s small idea to help you unlock your big ideas: Sleep more.

“I learned the hard way the value of sleep,” said Arianna Huffington at TEDWomen in 2010. “Two and a half years ago, I fainted from exhaustion, and I hit my head on my desk.” (Watch: Arianna Huffington: How to succeed? Get more sleep.) Since then, the media mogul has become a spokesperson for being better rested. Getting enough sleep, she suggests, leads to more productivity and better leadership — even though sleep experts still aren’t completely sure why we sleep or exactly how much we should.

Below, explore 16 articles and scientific papers on the evolving study of sleep, recommended by Huffington.